We propose to test a modification of the medium in which L. mesenteroides B-512F secretes dextransucrase by concanavalin A affinity chromatography and hydrophobic chromatography. We also propose to purify Strep. mutans OMZ176 polysaccharide sucrase by hydrophobic chromatography to obtain mutansucrase will be studied by pulse and chase experiments with 14C-sucrose. Acceptor reactions of 14C-glucose, fructose, maltose and dextran added to mutansucrase-3H-sucrose digests and acceptor reaction of dextranscurase-3H-sucrose with 14C-amylodextrin, mutan, and levan will be studied. Effects of the acceptor on the molecular size, solubility, and structure of the synthesized polysaccharide will be studied. Inhibition studies of dextransucrase with fluorosucroses, bacitracin A and F, and leucrose will be studied. The nature of the groups at the active site of dextransucrase will be studied using 14C-labeled irreversible dead-end inhibitors followed by proteinase degradation under denaturing conditions.